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Articles 1 - 30 of 448
Full-Text Articles in Engineering
Characterization Of Highly Doped N-Type And P-Type Silicon Carbide Ohmic Contacts, Tanner Rice
Characterization Of Highly Doped N-Type And P-Type Silicon Carbide Ohmic Contacts, Tanner Rice
Graduate Theses and Dissertations
Silicon Carbide (SiC) is a rather new material that possesses unparalleled properties when compared to Silicon. Due to its larger band gap alongside other thermal properties, SiC can survive in hotter, more radiation intensive environments, whether that be within the crust of the earth or in the reaches of space. As a desirable semiconductor for these applications, CMOS is an especially important device due to its low power consumption. However, creating a good contact between the metal and semiconductor optimally requires two different metals for the n -type and the p-type semiconductor. This greatly increases the processing time, as separate …
Ism-Band Energy Harvesting Wireless Sensor Node, Fnu Naveed
Ism-Band Energy Harvesting Wireless Sensor Node, Fnu Naveed
Graduate Theses and Dissertations
In recent years, the interest in remote wireless sensor networks has grown significantly, particularly with the rapid advancements in Internet of Things (IoT) technology. These networks find diverse applications, from inventory tracking to environmental monitoring. In remote areas where grid access is unavailable, wireless sensors are commonly powered by batteries, which imposes a constraint on their lifespan. However, with the emergence of wireless energy harvesting technologies, there is a transformative potential in addressing the power challenges faced by these sensors. By harnessing energy from the surrounding environment, such as solar, thermal, vibrational, or RF sources, these sensors can potentially operate …
A Real-Time Anpc Inverter Digital Twin With Integrated Design-For-Trust, Paulo Vitor Do Amaral Custodio
A Real-Time Anpc Inverter Digital Twin With Integrated Design-For-Trust, Paulo Vitor Do Amaral Custodio
Graduate Theses and Dissertations
The demand for renewable energy has increased over the last few years, and so has the demand for greater expectations within the energy market. This increasing trend has been accompanied by more significant usage of internet-connected devices (IoT), leading to critical electrical infrastructure being connected to the internet. Implementing internet connectivity with such devices and systems provides benefits such as improving the system's performance, facilitating irregularity and anomaly mitigation, and providing additional situational awareness for enhanced decision-making. However, enhancing the connected system with IoT introduces a drawback – a greater vulnerability to cyber-attacks. Cyber-attacks targeting critical infrastructure in the electrical …
Chip- And System-Level Reliability On Sic-Based Power Modules, Pengyu Lai
Chip- And System-Level Reliability On Sic-Based Power Modules, Pengyu Lai
Graduate Theses and Dissertations
The blocking voltage, switching frequency and temperature tolerance of power devices have been greatly improved due to the revolution of wide bandgap (WBG) materials, such as silicon carbide (SiC) and gallium nitride (GaN). Owing to the development of SiC-based power devices, the power rating, operating voltage, and power density of power modules have been significantly improved. However, the reliability of SiC-based power modules has not been fully explored yet. Thus, this dissertation focuses on the chip- and system-level reliability on SiC-based power modules. For chip-level reliability, this work focuses on on-chip SiC ESD protection devices for SiC-based integrated circuits (ICs). …
Partial Discharge Mitigation In Power Modules Using An Automation-Driven Design Rule Development Method, Shilpi Mukherjee
Partial Discharge Mitigation In Power Modules Using An Automation-Driven Design Rule Development Method, Shilpi Mukherjee
Graduate Theses and Dissertations
Power modules used for the conversion and conditioning of electrical power for applications like electric vehicles, more-electric aircraft, the power grid, etc., are largely designed manually by engineers. Design automation of power modules is starting to gain recognition as a timely and necessary alternative to intuitive manual design and fabrication. With increasing need for wide bandgap materials that can operate at higher voltages, and the need to make modules more compact, hazards like electrical breakdown are more likely. Partial discharge (PD) is a silent and invisible precursor to electrical breakdown. It is compounded with compaction, creating a potential for electrical …
Modeling & Small Signal Analysis Of Grid Forming Inverter, Kadesh Hepburn
Modeling & Small Signal Analysis Of Grid Forming Inverter, Kadesh Hepburn
Graduate Theses and Dissertations
There is a rising number of inverter-based resources (IBRs) being integrated with distribution systems are becoming a more common occurrence. With integration of IBRs inverters, power utilities are experiencing an increase of number of operations with regards to voltage and frequency support. To maintain grid stability and reliability, IBRs need to provide some of the services currently (or formerly) provided by synchronous generators. Interconnection standards, like the IEEE 1547. 2018 has include requirements for IBRs to have the capability to provide some of these services—such as frequency and voltage support—and the procurement and deployment of the services can be implemented …
Fabrication And Measurement Of Lt-Gaas Photoconductive Antennas And Arrays, Zachary Paul Uttley
Fabrication And Measurement Of Lt-Gaas Photoconductive Antennas And Arrays, Zachary Paul Uttley
Graduate Theses and Dissertations
This thesis presents the fabrication and measurement of LT-GaAs based terahertz (THz) photo conductive antennas (PCAs) and arrays. The LT-GaAs THz PCAs are fabricated to serve as reference devices to new 2D material black phosphorous (BP) based THz PCAs. The LT-GaAs and BP devices have identical metallic electrodes, allowing for a comparison of emitted THz intensity and bandwidth. All PCAs have been measured using an open bench pulsed time-domain spectroscopy (TDS) system with a usable bandwidth from 0.1-4 THz, pumped with a 780nm Ti:Sapphire femtosecond laser. The results have shown LT-GaAs devices outperforming BP devices in signal amplitude and bandwidth …
Achieving High Renewable Energy Integration In Smart Grids With Machine Learning, Yaze Li
Achieving High Renewable Energy Integration In Smart Grids With Machine Learning, Yaze Li
Graduate Theses and Dissertations
The integration of high levels of renewable energy into smart grids is crucial for achieving a sustainable and efficient energy infrastructure. However, this integration presents significant technical and operational challenges due to the intermittent nature and inherent uncertainty of renewable energy sources (RES). Therefore, the energy storage system (ESS) has always been bound to renewable energy, and its charge and discharge control has become an important part of the integration. The addition of RES and ESS comes with their complex control, communication, and monitor capabilities, which also makes the grid more vulnerable to attacks, brings new challenges to the cybersecurity. …
Understanding Peripheral Blood Pressure Signals: A Statistical Learning Approach, Md Abul Hayat
Understanding Peripheral Blood Pressure Signals: A Statistical Learning Approach, Md Abul Hayat
Graduate Theses and Dissertations
Proper estimation of body fluid status for human or animal subjects has always been a challenging problem. Accurate and timely estimate of body fluid can prevent life threatening conditions under trauma and severe dehydration. The main objective of this research is the estimation, classification and detection of dehydration in human and animal subjects using peripheral blood pressure (PBP) signals. Peripheral venous pressure (PVP) and peripheral arterial pressure (PAP) signals have been investigated in this research. Both PVP and PAP signals are PBP signals. A dataset of PVP signals was collected using standard peripheral intravenous catheters from human subjects suffering from …
Optocoupler Integration Of Ltcc-Based Gate Driver In A Sic Power Module, Michael Oghenekome Otobo
Optocoupler Integration Of Ltcc-Based Gate Driver In A Sic Power Module, Michael Oghenekome Otobo
Graduate Theses and Dissertations
The growing demand for electrical energy in today’s industrialized economy has driven the need for innovative approaches to meet diverse application requirements. Notably, advancements have been made in the field of power electronic systems, as reliable power electronic converters are essential for managing multiple power sources and loads. However, the development of these systems poses challenges related to power device switching speed, system weight and size, and power losses. The integration of a gate driver into a SiC power module offers a solution to many of these challenges, thereby driving the advancement of electrical power density expansion. An LTCC-based gate …
Design Of A Sigma-Delta Adc In 65nm Cmos Process, Michael Lee Thompson Iii
Design Of A Sigma-Delta Adc In 65nm Cmos Process, Michael Lee Thompson Iii
Electrical Engineering Undergraduate Honors Theses
Analog and digital signals both play a vital role in electrical engineering and the technology of today. As the role of electrical and computer engineers becomes more deeply involved in the development of new technology, an understanding of how these signals are utilized, and what they represent, is a necessity. Due to the inherent limitations involved with analog signals, there is a need for these signals to be accurately and efficiently converted to digital signals for processing. The job of the analog-to-digital converter, or ADC, is to receive this analog input signal (voltage or current) and create a digital representation …
Analysis Of An Isolated Bidirectional Ćuk Converter, Yeny Hau Chen
Analysis Of An Isolated Bidirectional Ćuk Converter, Yeny Hau Chen
Graduate Theses and Dissertations
The objective of this thesis is to perform an analysis of the isolated bidirectional Ćuk dc-dc converter topology and demonstrate the advantages and operation of this configuration through simulations using MATLAB/SimulinkTM and measurements collected from a 1.5-kW prototype tested at the Engineering Research Center (ENRC) laboratory of the University of Arkansas. The idea of integrating an active-clamp snubber circuit on each side of the converter, proposed by Dr. Sudip Mazumder from the University of Illinois, Chicago, limits the additional voltage stresses on the components due to the energy from the transformer’s leakage inductance. This is studied in this thesis to …
The Growth And Characterization Of Inn Quantum Dots Using Droplets Epitaxy In Mbe, Malak Refaei
The Growth And Characterization Of Inn Quantum Dots Using Droplets Epitaxy In Mbe, Malak Refaei
Graduate Theses and Dissertations
III-nitride semiconductor material systems offer great potential for next-generation optoelectronic devices due to their direct bandgaps, which vary from 0.7 eV (InN) to 3.5 eV (GaN) to 6.2 eV (AlN), as well as their other unique properties. InN has gained much less attention than GaN and AlN within this family of semiconductors due to its complicated low-temperature growth. However, the prediction that an InN quantum well on GaN can become a two-dimensional (2D) topological insulator has resulted in expanding the research interest in InN. At the same time, this renewed interest has begun to reveal that the formation of an …
Stream Processor Development Using Multi-Threshold Null Convention Logic Asynchronous Design Methodology, Wassim Khalil
Stream Processor Development Using Multi-Threshold Null Convention Logic Asynchronous Design Methodology, Wassim Khalil
Graduate Theses and Dissertations
Decreasing transistor feature size has led to an increase in the number of transistors in integrated circuits (IC), allowing for the implementation of more complex logic. However, such logic also requires more complex clock tree synthesis (CTS) to avoid timing violations as the clock must reach many more gates over larger areas. Thus, timing analysis requires significantly more computing power and designer involvement than in the past. For these reasons, IC designers have been pushed to nix conventional synchronous (SYNC) architecture and explore novel methodologies such as asynchronous, self-timed architecture. This dissertation evaluates the nominal active energy, voltage-scaled active energy, …
Analyzing Energy Use From Arkansas Public School Buildings, Oscar Morton
Analyzing Energy Use From Arkansas Public School Buildings, Oscar Morton
Biological and Agricultural Engineering Undergraduate Honors Theses
Energy is a key global resource in society and greenhouse gas (GHG) emissions related to the consumption of energy have detrimental effects on the planet. With energy consumption increasing, exponential population growth, and diminishing natural resources necessary for energy production, the relevance of energy efficiency is dramatically increasing. In this project, I analyzed energy usage data from a set of public school buildings from one school district in northwest Arkansas from 2018, before targeted energy efficiency practices were implemented, through 2022 to see if energy usage changed over this short period. The objectives of analyzing energy data were to determine …
Simulating Dielectric Barrier Plasma Actuators With Varying Geometries, Cass Wiederkehr
Simulating Dielectric Barrier Plasma Actuators With Varying Geometries, Cass Wiederkehr
Mechanical Engineering Undergraduate Honors Theses
The idea of Ionic Wind Propulsion has long been a topic of research for whether or not it can be used as a practical power source for flight. MIT researchers proved in 2018 that a plane with zero moving parts powered by Ionic Wind Propulsion was possible, and sustained flight could work with an internal power supply. However, due to the thin wire electrodes required to generate the ion cloud that made such propulsion possible, large amounts of drag rendered the plane extremely inefficient and impractical. Dielectric Barrier Discharge Devices (DBDs) are being investigated as to whether they can serve …
Evaluation Of Dual Band J-Pole Antennas To Serve Drone-Mountable Ham Radio Repeater, Jeremiah Wimer
Evaluation Of Dual Band J-Pole Antennas To Serve Drone-Mountable Ham Radio Repeater, Jeremiah Wimer
Electrical Engineering Undergraduate Honors Theses
The portable “roll-up” Dual-Band J-pole antenna model (commonly referred to as DBJ-2) is found to be the most favorable J-pole antenna design for serving a drone-mountable ham radio repeater. In addition to being light in weight, inexpensive to construct, and weather-resilient, the DBJ-2 offers the greatest Standing Wave Ratio (SWR) in the Very High Frequency (VHF) and Ultra High Frequency (UHF) bands compared to the other J-pole antenna designs evaluated. Enclosed is a brief overview of antenna design theory, as well as an exploration of various other J-pole antenna designs, and a clear rationale for selecting the DBJ-2 antenna design …
Fabrication Of Black Phosphorus Terahertz Photoconductive Antennas, Nathan Tanner Sawyers
Fabrication Of Black Phosphorus Terahertz Photoconductive Antennas, Nathan Tanner Sawyers
Physics Undergraduate Honors Theses
Terahertz (THz) photoconductive antennas (PCAs) using 40nm thin-film flakes of black phosphorus (BP) and hexagonal boron nitride (hBN) have been shown computationally to be capable of THz emission comparable to those based on GaAs [2]. In this paper, I briefly describe the scientific and practical interest in THz emissions and explain what warrants research into black phosphorus as a photoconductive semiconductor in THz devices. Furthermore, I outline the basic principle of how these antennas work and mention alternative designs produced by other researchers in the past. Finally, I summarize the fabrication process of these antennas, as well as the measurements …
Modbus Rtu For Embedded Cyber Secure Inverter Controller, Brady Mcbride
Modbus Rtu For Embedded Cyber Secure Inverter Controller, Brady Mcbride
Graduate Theses and Dissertations
The Modbus communication protocol is a widely adopted communication standard in industrial control systems. This communication protocol is known for being reliable and straightforward to implement while being versatile in terms of its operating parameters while supporting multiple formats over various hardware infrastructures and architectures. Many intelligent devices such as Programmable Logic Controllers (PLCs), Human-Machine Interfaces (HMIs), Internet-of-Things (IoT), and various Operational Technologies (OT) utilize Modbus for their communication systems. These types of systems must communicate with each other through a standardized and central communication process. To support the integration of these modular systems, a Field-Programmable Gate Array (FPGA) can …
Design Approaches To Enhance Power Density In Power Converters For Traction Applications, Shamar Christian
Design Approaches To Enhance Power Density In Power Converters For Traction Applications, Shamar Christian
Graduate Theses and Dissertations
This dissertation presents a design strategy to increase the power density for automotive Power Conversion Units (PCUs) consisting of DC-DC and DC-AC stages. The strategy significantly improves the volumetric power density, as evident by a proposed PCU constructed and tested having 55.6 kW/L, representing an 11.2 % improvement on the Department of Energy’s 2025 goal of 50 kW/L for the same power electronics architecture. The dissertation begins with a custom magnetic design procedure, based on optimization of a predetermined C-core geometrical relationship and custom Litz wire. It accounts for electrical and thermal tradeoffs to produce a magnetic structure to best …
Multiple Output Power Supply Using Toroidal Transformers For Medium Voltage Active Gate Drivers, Samhitha Venkata Machireddy
Multiple Output Power Supply Using Toroidal Transformers For Medium Voltage Active Gate Drivers, Samhitha Venkata Machireddy
Graduate Theses and Dissertations
When operating in high power applications, power devices dissipate tens or hundreds of watts of power in the form of heat. The ability of the power devices to withstand power and dissipation of heat across the power devices becomes a prominent requirement in designing the power converter. This challenge demands a power converter design to be more effective and consistent which factors in size, cost, weight, power density and reliability. This study aims to propose a gate driver isolated power supply design that can be used in medium voltage applications (e.g., up to 10 kV) while respecting the principle of …
Gate-Controlled Quantum Dots In Two-Dimensional Tungsten Diselenide And One-Dimensional Tellurium Nanowires, Shiva Davari Dolatabadi
Gate-Controlled Quantum Dots In Two-Dimensional Tungsten Diselenide And One-Dimensional Tellurium Nanowires, Shiva Davari Dolatabadi
Graduate Theses and Dissertations
This work focuses on the investigation of gate-defined quantum dots in two-dimensional transition metal dichalcogenide tungsten diselenide (WSe2) as a means to unravel mesoscopic physical phenomena such as valley-contrasting physics in WSe2 flakes and its potential application as qubit, as well as realizing gate-controlled quantum dots based on elementaltellurium nanostructures which may unlock the topological nature of the host material carriers such as Weyl states in tellurium nanowires.The fabrication and characterization of gate-defined hole quantum dots in monolayer and bilayer WSe2 are reported. The gate electrodes in the device design are located above and below the WSe2 nanoflakes to accumulate …
Design And Comparison Of Asynchronous Fft Implementations, Julie Bigot
Design And Comparison Of Asynchronous Fft Implementations, Julie Bigot
Graduate Theses and Dissertations
Fast Fourier Transform (FFT) is a widely used digital signal processing technology in a large variety of applications. For battery-powered embedded systems incorporating FFT, its physical implementation is constrained by strict power consumption, especially during idle periods. Compared to the prevailing clocked synchronous counterpart, quasi-delay insensitive asynchronous circuits offer a series of advantages including flexible timing requirement and lower leakage power, making them ideal choices for these systems. In this thesis work, various FFT configurations were implemented in the low-power Multi-Threshold NULL Convention Logic (MTNCL) paradigm. Analysis illustrates the area and power consumption trends along the changing of the number …
Electrical Modeling For Dynamic Performance Prediction And Optimization Of Mcpms Layout, Quang Minh Le
Electrical Modeling For Dynamic Performance Prediction And Optimization Of Mcpms Layout, Quang Minh Le
Graduate Theses and Dissertations
In recent years, the fast development of Multichip Power Modules (MCPM) packaging and Wide Bandgap (WBG) technology has enabled higher voltage and current ratings, better thermal performance, lower parasitic parameters, and higher mechanical reliability. However, the design of the MCPM layout is a multidisciplinary problem leading to many time-consuming analyses and tedious design processes. Because of these challenges, the design automation tool for MCPM layout has become an emerging research area and gained much attention from the power electronics community. The two critical objectives of a design automation tool for MCPM layout are fast and accurate models for design insights …
Hybrid Multilevel Converters With Internal Cascaded/Paralleled Structures For Mv Electric Aircraft Applications, Fei Diao
Graduate Theses and Dissertations
Using on-board medium voltage (MV) dc distribution system has been a megatrend for next-generation electric aircraft systems due to its ability to enable a significant system mass reduction. In addition, it makes electric propulsion more feasible using MV power electronic converters. To develop high-performance high-density MV power converters, the emerging silicon carbide (SiC) devices are more attractive than their silicon (Si) counterparts, since the fast switch frequency brought by the SiC can effectively reduce the volume and weight of the filter components and thus increase the converter power density. From the converter topology perspective, with the MV dc distribution, the …
Data-Driven Deep Learning-Based Analysis On Thz Imaging, Haoyan Liu
Data-Driven Deep Learning-Based Analysis On Thz Imaging, Haoyan Liu
Graduate Theses and Dissertations
Breast cancer affects about 12.5% of women population in the United States. Surgical operations are often needed post diagnosis. Breast conserving surgery can help remove malignant tumors while maximizing the remaining healthy tissues. Due to lacking effective real-time tumor analysis tools and a unified operation standard, re-excision rate could be higher than 30% among breast conserving surgery patients. This results in significant physical, physiological, and financial burdens to those patients. This work designs deep learning-based segmentation algorithms that detect tissue type in excised tissues using pulsed THz technology. This work evaluates the algorithms for tissue type classification task among freshly …
Reliability Enhancing Control Algorithms For Two-Stage Grid-Tied Inverters, Yuheng Wu
Reliability Enhancing Control Algorithms For Two-Stage Grid-Tied Inverters, Yuheng Wu
Graduate Theses and Dissertations
In the photovoltaic (PV) generation system, two types of grid-tied inverter systems are usually deployed: the single-stage grid-tied inverter system and the two-stage grid-tied inverter system. In the single-stage grid-tied inverter system, the input of the inverter is directly connected to the PV arrays, while an additional dc-dc stage is inserted between the PV arrays and the dc-ac inverter in the two-stage design. The additional dc-dc stage could provide a stable dc-link voltage to the inverter, which also enables new design possibilities, including the multi-MPPT operation and solar-plus-storage application. Thus, the two-stage grid-tied inverter has been widely used in the …
Using Molecular Dynamics Simulations To Decipher Mechanistic Details Of Biomolecular Processes Of Biology And Biotechnology Oriented Applications, Adithya Polasa
Graduate Theses and Dissertations
Researchers in chemistry and biology often utilize computer simulations, in conjunction with experimental data, to model and predict the structures, energies, kinetics, processes, and functions of the systems that are their focus of study, ranging from single molecules to whole viruses. Here, we use molecular dynamics (MD) techniques to gain a deeper understanding of biomolecular processes in biology and biotechnology-oriented applications. Using a mixture of equilibrium and non-equilibrium MD simulations, this work describes the insertion process of YidC at the atomic level. In order to better comprehend the insertion process, several docking models of YidC-Pf3 in the lipid bilayer were …
Controller Platform Design And Demonstration For An Electric Aircraft Propulsion Driv, Rosten Sweeting
Controller Platform Design And Demonstration For An Electric Aircraft Propulsion Driv, Rosten Sweeting
Graduate Theses and Dissertations
With the growth in the aerospace industry there has been a trend to optimize the performance of an aircraft by reducing fuel consumption and operational cost. Recent advancements in the field of power electronics have pushed towards the concepts of hybrid electric aircraft also known as more electrical aircrafts. In this work, a custom controller board for an electric aircraft propulsion drive was designed to drive a permanent magnet synchronous motor. Design of the controller board required knowledge of the topology selection and power module selections. Simulations of the system were performed using MATLAB/Simulink to analyze the overall performance of …
A Memory-Centric Customizable Domain-Specific Fpga Overlay For Accelerating Machine Learning Applications, Atiyehsadat Panahi
A Memory-Centric Customizable Domain-Specific Fpga Overlay For Accelerating Machine Learning Applications, Atiyehsadat Panahi
Graduate Theses and Dissertations
Low latency inferencing is of paramount importance to a wide range of real time and userfacing Machine Learning (ML) applications. Field Programmable Gate Arrays (FPGAs) offer unique advantages in delivering low latency as well as energy efficient accelertors for low latency inferencing. Unfortunately, creating machine learning accelerators in FPGAs is not easy, requiring the use of vendor specific CAD tools and low level digital and hardware microarchitecture design knowledge that the majority of ML researchers do not possess. The continued refinement of High Level Synthesis (HLS) tools can reduce but not eliminate the need for hardware-specific design knowledge. The designs …